More than 50 workers at a military factory in central Syria were killed in a bombing earlier this week, an opposition watchdog which monitors violence in Syria said on Friday.
The Syrian Observatory for Human Rights said 54 people died in Wednesday's explosion which struck their bus as they were preparing to return home at the end of their shift, and the number could rise further.
The Observatory said 11 of the victims from the bombing in Buraq, about 10 km (six miles) south of the city of Hama, were women. The workers were from cities of Homs, Hama and the town of Salamiyah.
There has been no claim of responsibility for the bombing, which angered many Syrian activists, who blamed Islamist hardliners for the attack. Some described it as "terrorist" attack which targeted civilians.
"They are workers, they are civilians. Some people need to work to feed their families. This does not make them criminals," said an activist from Hama province who declined to be named.
The Islamist Nusra Front last month said it was behind a car bombing which killed 42 people, including women and children in Salamiyah. The target of that attack was a pro-government militia, they said. Activists in Salamiyah posted pictures of children and young people who were killed in the attack.
(Reporting by Dominic Evans; Editing by Jon Boyle)